Radiation images such as X-ray images have been used widely for diagnoses of medical conditions in medical sites. In particular, radiation images of an intensifying screen-film type wherein high sensitivity and high image quality have been attained in a long history are still used in the medical sites all over the world as an imaging system having the high reliability and cost effectiveness. In recent years, a digital type radiation image detector represented by a flat panel radiation detector [FPD (Flat Panel Detector)] is also making an appearance, which makes it possible to obtain radiation images as digital information, to conduct image processing freely, or to transmit image information instantly.
The aforesaid detector has a so-called “scintillator plate” that converts radiation into fluorescence. The scintillator plate is one that receives radiation transmitted through an object and emits instantly fluorescence having intensity corresponding to a dose of the radiation, and it has a structure in which a phosphor layer is formed on a support.
Meanwhile, the phosphor layer mentioned above is made of a material (cesium iodide) having deliquescent properly in many cases, and it has drawbacks that it tends to be deteriorated with the passage of time accordingly. Therefore, a protective layer is formed on the surface of the phosphor layer to protect it from chemical degeneration and physical impact shock. For example, as a protective layer of that kind, those employing polyparaxylene are disclosed in Patent Document 1, and those employing an organic film made of parylene are disclosed in Patent Document 2. In addition to the foregoing, organic polymer films of polypropylene or of polyethylene terephthalate are known.
(Patent Document 1) Japanese Patent O.P.I. Publication No. 2000-9846
(Patent Document 2) Japanese Patent O.P.I. Publication No. 2000-284053